WHOOPIE PIES WITH GERMAN BUTTERCREAM RECIPE - (4.5/5)

Steps:

• 1. Preheat the oven to 350 degrees F (180 degrees C). Line two baking sheets with parchment paper. 2. For the dough cream butter and sugar. Beat together eggs and vanilla and add. Mix flour, baking powder, baking soda and salt and add. Dissolve cocoa in hot water and add, alternating with buttermilk. Stir until smooth. 3. Fill about two-thirds of a pastry bag fitted with a large round tip with dough and squirt about one tablespoon for each cookie onto the lined baking sheet, leaving at least ½ inch distance between them. Bake one baking sheet after the other in the preheated oven for 12 minutes. 4. Transfer the parchment paper with the cookies to a cake rack and let cool completely before carefully removing the cookies. Place them on the cake rack and store in a cool dry place until you are ready to fill them. 5. For the buttercream dissolve the cornstarch in a few tablespoons of the milk. Bring the rest of the milk to a boil. Add the cornstarch, vanilla and sugar and cook until it thickens, stirring constantly. 6. Remove from the heat and add the beaten egg yolks and salt. Whisk to incorporate. Return to the heat and simmer over very low heat until it thickens, stirring constantly. Do not boil, or the eggs will curdle. 7. Remove from the heat and cool to lukewarm. Slowly add the butter, which must have the same temperature. Whisk until smooth. Refrigerate overnight. The buttercream should be fully set. 8. Spread a generous amount of buttercream on a completely cooled cookie and top with another cookie. Place the whoopie pies in an airtight container with layers of wax paper between them. Refrigerate.